Max,
I have noticed on some double rifles, the action doesn't have a real "circle" machined in, but instead, they have a straight line angled surface, obviously due to fact that a straight line surface is much easier to machine in. A true "circle" surface obviously gives more surface area, recoil contact, than does a straight line surface, but I am not sure if that difference is enough to merit consideration. Please comment, giving your thoughts about a straight line angled surface, as opposed to a true "circle" surface.

Also, I have noticed that some double rifles have a HARDENED steel insert dovetailed into the lump, that mates with the action "circle." What are your thoughts about this?